Acute promyelocytic leukemia with CD59 deficiency.

CD59 is a phosphatidyl inositol-anchored protein (which is lost in paroxysmal nocturnal hemoglobinuria (PNH) cells) with the capacity to block the formation of membrane attack complex, and protects host cells from autologous complement-mediated cytolysis. We found a patient with acute promyelocytic leukemia (APL) accompanied by disseminated intravascular coagulation (DIC), the cells of which were CD59-negative. Although the CD59 deficiency in the malignant cells was not related to PNH, we offered the possibility that DIC was induced by APL lysis secondary to the deficiency of CD59.